Oil drain plug



FIG. 1 is a front and top perspective view of an oil drain plug, showing our new design;

FIG. 2 is a rear and bottom perspective view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a rear elevation view thereof;

FIG. 5 is a left side elevation view thereof;

FIG. 6 is a right side elevation view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof.

The broken lines in the figures illustrate portions of the oil drain plug that form no part of the claimed design. 

CLAIM The ornamental design for an oil drain plug, as shown and described. 